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Question:

Doc,

So, question #1 - Can I put down 1/2" solid Mesquite on top of my slab (assuming I follow all the other recommendations in your article concerning moisture and flatness testing)? If so, what's the maximum width you would recommend?

Problem #2 - the wallboards extend straight to the slab. Have you ever encountered this before? Aren't you supposed to slide the floor under the wallboard for purposes of expansion? How can I do this if the board runs all the way to the slab? Should I remove all the wallboard and take 1/2" off with a band saw? Is there a horizontal circular saw that can cut this without me removing the wallboard?

Finally, we are removing the old carpet and wondering what to do with the old carpet tack strip nails. Every time I pry the nail that holds the strip down out of the concrete, it takes some concrete with it, sometimes as much as 1.5" in diameter. Is there a better way to remove these nails? Should I use my dremel and just cut them off, or is it really even something to worry about? Thanks for all of your help.

Steve

Answer:



Dear Steve

By now you've read my "wood floor on concrete" article and you see all the choices, good to not so good. And the solid wood strip laid directly is the not-so-good. Before I start into your answers (to lots of questions, whew !), I'd like to direct you to Kentucky Wood Floors. They still make traditional patterned solid wood (3/4") thick parquet. Take a look at the photos of these elegant floors, these are the real Mc Coy. Also they do produce a laminated (engineered) wood strip floor, that has a top wear layer of 1/4". Installers are raving about the way this material fits, and stays in place as you lay it. It's the best of this sort of flooring made by a company in this business for over 25 years now. Here's the link :

http://www.kentuckywood.com/

Now as to your question. While it is true that mesquite has very small movement in service, it is just about similar to teak, cocobolo, and even quarter sawn red oak. But be warned that there is some movement, because this is solid wood after all. You cannot glue down a great expanse of any kind of solid wood strip floor (more that 20 feet in width) and have it perform well, unless you keep indoor relative humidity levels within a 20% RANGE. And the ideal range for hardwood floors is 40-60%. Next time you visit a museum check out the accurate electronic hygrometers on the walls. They keep the collections pegged at 50% RH all year long.

Mesquite has a projected seasonal range of movement of .0013. So given a safety factor of +25% even mesquite will expand and contract .4" over just 20 feet of width. This when the EMC (equilibrium moisture content) of the WOOD changes from 6% in the winter heating season, up to 12% in the middle of a muggy summer (this would be caused by a more realistic indoor humidity range of 30%).

A site finished floor will reach these extremes but much slower than a prefinished floor. Any gaps that form will be small and more evenly distributed with a floor well sanded and finished. This projected movement is based on a more realistic indoor humidity range of 30%. The only problem with a site finished mesquite, is that it will be a bear to sand. Choose a well seasoned professional floor sander in your area, so the coarse sanding marks don't show through if you go this route.

So yes, this stuff is comparatively stable, as long as you stick to the sizes I recommended in the article. I'll repeat this here :

"These have to be specially milled for this purpose. They will need to be no more than 2 feet long, and have a flat underside. And they should not be more than 1/2" thick and 2" wide. If you look at the standard strip floor you will notice it has a grooved bottom which will not contact the glue as well as the flat milled bottom". Just remember the vender is trying to sell you something, I am not. Also the key here is "flat milled bottoms". It's not an easy installation unless the wood is perfectly milled. Have the salesman provide some references of professional installers that have used this particular mesquite product, they will tell you how well the product is made. If the store refuses this, go somewhere else.

To the second question, just remove the wall board (up north we call it baseboard, or molding) carefully and install the floor with the appropriate expansion gaps, and replace the baseboard on top of the floor after the job is done. It will neatly cover the small gaps. If this is really thin baseboard, you can remove it and even undercut the drywall (don't break the vapor barrier) by scoring the drywall with a knife and removing that small strip. Then replace the baseboard. This will give a wider expansion gap as drywall is 1/2" thick at least.

Removing the baseboard is tricky without snapping this thin modern stuff, so use a backer board to protect the wall as you pry it off with a tool like this :

http://www.leevalley.com/wood/page.asp?SID=x=1x=32014x=1,43456,43399

But if you don't want to remove them you can buy or maybe rent the Crain jamb saw at http://www.craintools.com/fs-specialtysaws.html The last question, just pop the carpet strips off, the damage occurred when the nail was hammered in anyway. Fill with a non shrinking mortar, it's easy.

You may also find these articles helpful:

1. Installing Hardwood Floors On Concrete Slabs

2. Plank Floor: What Special Considerations This Type Of Floor Raises

3. How To Chemically Strip Wood Floors without dust!

4. How To Sand Wood Floors Without Leaving Machine Marks

5. How To Take Care Of Your Health And Safety when Installing, Finishing, Repairing or Cleaning your wood floors